Braking control system

Abstract

A braking control system 60 includes a first braking ECU 70 for operating a first electric parking actuator 31, and a redundant ECU 90 for operating a second electric parking actuator 32. When the first braking ECU 70 receives a parking brake operation request via a global communication line 201, the first braking ECU 70 operates the first electric parking actuator 31 on the basis of the parking brake operation request, and transmits an operation instruction corresponding to the parking brake operation request to the redundant ECU 90 via a braking communication line 61. The redundant ECU 90 operates the second electric parking actuator 32 on the basis of the operation instruction received via the braking communication line 61 when the first braking ECU 70 is normal, and operates the second electric parking actuator 32 on the basis of a parking brake operation request received via a second global communication line 202 when abnormality occurs in the first braking ECU 70.

Description

Braking Control System

[0001] The present invention relates to a braking control system mounted on a vehicle.

[0002] Patent Document 1 discloses a vehicle equipped with an automatic transmission and an electric parking device. The electric parking device includes a first electric parking actuator that generates a parking braking force on a first wheel among a plurality of wheels, and a second electric parking actuator that generates a parking braking force on a second wheel among the plurality of wheels. The braking system of the vehicle includes an upstream hydraulic braking device and a downstream hydraulic braking device as braking devices that generate normal braking forces on the plurality of wheels, as well as a first controller that controls the downstream hydraulic braking device and a second controller that controls the upstream hydraulic braking device.

[0003] When the parking brake switch is operated, the first controller operates the first electric parking actuator to generate parking braking force on the first wheel. The first controller also transmits an operation instruction to the second controller via the in-vehicle network. The second controller operates the second electric parking actuator based on the received operation instruction to generate parking braking force on the second wheel.

[0004] European Patent No. 3529118

[0005] In recent years, there has been a demand for redundancy in electric parking devices.

[0006] A braking control system for solving the above problem is applied to a vehicle including a first wheel and a second wheel, a first electric parking actuator configured to generate a parking braking force on the first wheel, and a second electric parking actuator configured to generate a parking braking force on the second wheel. The braking control system includes a first control device that operates the first electric parking actuator and a second control device that operates the second electric parking actuator. Each of the first control device and the second control device is capable of receiving a parking brake operation request, which is a request for parking braking, via a first in-vehicle network. The second control device is capable of communicating with the first control device via a second in-vehicle network. When the first control device receives the parking brake operation request via the first in-vehicle network, the first control device operates the first electric parking actuator based on the parking brake operation request and transmits an operation command corresponding to the parking brake operation request to the second control device via the second in-vehicle network. When the first control device is normal, the second control device operates the second electric parking actuator based on the operation instruction received via the second in-vehicle network, and when an abnormality occurs in the first control device, the second control device operates the second electric parking actuator based on the parking brake operation request received via the first in-vehicle network.

[0007] The braking control system described above has the effect of making the electric parking device redundant.

[0008] Fig. 1 is a schematic diagram of a vehicle equipped with a brake control system according to this embodiment. Fig. 2 is a diagram showing the brake control system of Fig. 1 and an electric parking device controlled by the brake control system. Fig. 3 is a flowchart showing a series of processes executed by a second brake ECU (a) and a redundant ECU (b) when determining that an abnormality has occurred in a first brake ECU included in the brake control system of Fig. 1 or that communication using a brake communication line is not normal. Fig. 4 is a flowchart showing a series of processes executed by a second brake ECU (a) and a first brake ECU (b) when determining that an abnormality has occurred in a redundant ECU included in the brake control system of Fig. 1. Fig. 5 is a flowchart showing a series of processes executed by the integrated ECU, (b) a flowchart showing a series of processes executed by the redundant ECU, and (c) a flowchart showing a series of processes executed by the first brake ECU and the second brake ECU when it is determined that communication using the first global communication line provided in the vehicle of Fig. 1 is abnormal. Fig. 6 is a flowchart showing a series of processes executed by the first brake ECU and (b) a flowchart showing a series of processes executed by the redundant ECU when the brake control system of Fig. 1 is normal. Fig. 7 is a flowchart showing a series of processes executed by the redundant ECU when it is determined that an abnormality has occurred in the first brake ECU provided in the brake control system of Fig. 1. Fig. 8 is a flowchart showing a series of processes executed by the first brake ECU when it is determined that an abnormality has occurred in the redundant ECU provided in the brake control system of Fig. 1. 9A is a flowchart showing a series of processes executed by the first brake ECU when it is determined that an abnormality has occurred in the brake communication line provided in the brake control system of FIG. 1, and FIG. 9B is a flowchart showing a series of processes executed by the redundant ECU.10A is a flowchart showing a series of processes executed by the first brake ECU when it is determined that communication using the first global communication line provided in the vehicle of FIG. 1 is abnormal, and FIG. 10B is a flowchart showing a series of processes executed by the redundant ECU.

[0009] An embodiment of a brake control system will be described with reference to Figs. 1 to 10. <Vehicle Configuration> Fig. 1 shows a vehicle 10 to which a brake control system 60 is applied. Fig. 2 shows the brake control system 60. As shown in Figs. 1 and 2, the vehicle 10 further includes a plurality of wheels, friction brakes 20 in the same number as the wheels, a hydraulic braking device 25, and an electric parking device 30. The plurality of wheels includes a first wheel 11 and a second wheel 12. An example of the first wheel 11 and the second wheel 12 is the rear wheels.

[0010] Each of the plurality of friction brakes 20 has a rotating body 21 that rotates integrally with the corresponding wheel, a friction material 22, and a wheel cylinder 23. The friction brake 20 is configured to generate a braking force at the corresponding wheel by pressing the friction material 22 against the rotating body 21. The higher the hydraulic pressure in the wheel cylinder 23, the greater the force pressing the friction material 22 against the rotating body 21, and therefore the greater the braking force generated at the wheel.

[0011] Of the multiple wheel cylinders 23, the wheel cylinder 23 provided on the first wheel 11 is referred to as the "first wheel cylinder," and the wheel cylinder 23 provided on the second wheel 12 is referred to as the "second wheel cylinder."

[0012] The hydraulic braking device 25 includes a first hydraulic braking device 26 and a second hydraulic braking device 27. Each of the first hydraulic braking device 26 and the second hydraulic braking device 27 is configured to be able to adjust the hydraulic pressure of the plurality of wheel cylinders 23. The first hydraulic braking device 26 is configured to be able to adjust the hydraulic pressure of the plurality of wheel cylinders 23 individually. The second hydraulic braking device 27 is configured to be able to generate, in the plurality of wheel cylinders 23, hydraulic pressure corresponding to a required braking force, which is a required value of braking force for the vehicle 10. An example of the configuration of the first hydraulic braking device 26 and the second hydraulic braking device 27 is disclosed in Japanese Patent Application Laid-Open No. 2024-76857.

[0013] The electric parking device 30 includes a first electric parking actuator 31 and a second electric parking actuator 32. The first electric parking actuator 31 is configured to generate a parking braking force at the first wheel 11. The second electric parking actuator 32 is configured to generate a parking braking force at the second wheel 12. Each of the electric parking actuators 31, 32 has an electric motor. The electric parking actuators 31, 32 can generate a parking braking force at the wheel in accordance with the drive of the electric motor. For example, when the electric motor is driven, the friction material 22 of the friction brake 20 is pressed against the rotating body 21, thereby generating a parking braking force at the wheels 11, 12. An example of the configuration of the electric parking actuators 31, 32 is disclosed in Japanese Patent Application Laid-Open No. 2022-85637.

[0014] <First in-vehicle network> The first in-vehicle network of the vehicle 10 will be described with reference to Figures 1 and 2. The vehicle 10 is equipped with a plurality of electronic control units. Hereinafter, the electronic control units will be referred to as "ECUs." ECU is an abbreviation for "Electronic Control Unit." The vehicle 10 is equipped with a first in-vehicle network for communication between the plurality of ECUs. The first in-vehicle network has a plurality of global communication lines. An example of a global communication line is a CAN bus. "CAN" is an abbreviation for "Control Area Network."

[0015] The multiple global communication lines include a first global communication line 201 and a second global communication line 202. <ECUs Other than ECUs Constituting the Brake Control System> The vehicle 10 includes an integrated ECU 51 and a shift ECU 52 as ECUs other than ECUs constituting the brake control system 60. The integrated ECU 51 transmits various information, requests, and commands to the other ECUs via the first in-vehicle network. For example, when an occupant of the vehicle 10 operates the parking brake operation switch 41, the integrated ECU 51 transmits a parking brake operation request, which is a request related to parking braking, to the first global communication line 201 and the second global communication line 202, as indicated by arrow X1 in FIG. 2 . The parking brake operation switch 41 is an operation unit operated by the occupant to activate the electric parking device 30. For example, the parking brake operation switch 41 is installed in the vehicle cabin.

[0016] The parking brake operation request includes an apply request and a release request. The apply request is a request to generate parking braking force. The release request is a request to release the state in which parking braking force is being applied.

[0017] The shift ECU 52 controls a shift device provided in the vehicle 10. The shift ECU 52 transmits, to the second global communication line 202, range information that corresponds to the shift range selected by the shift device.

[0018] 1 and 2, the brake control system 60 includes a plurality of ECUs related to vehicle braking. The plurality of ECUs includes a first brake ECU 70, a second brake ECU 80, and a redundant ECU 90.

[0019] The first brake ECU 70 activates the first hydraulic brake device 26. The first brake ECU 70 activates the first electric parking actuator 31. In this respect, the first brake ECU 70 corresponds to the "first control device."

[0020] The first brake ECU 70 has a processing circuit 71 and a drive circuit 73. The processing circuit 71 has a CPU and a memory that stores control programs executed by the CPU. The control programs include a control program for operating the first hydraulic braking device 26 and a control program for operating the first electric parking actuator 31. The CPU executes the control programs in the memory, allowing the processing circuit 71 to operate the first hydraulic braking device 26 and the first electric parking actuator 31.

[0021] The drive circuit 73 is a circuit for driving the electric motor of the first electric parking actuator 31. When the drive circuit 73 operates based on a command from the processing circuit 71, the drive circuit 73 outputs a drive signal. The electric motor is driven based on the drive signal, thereby operating the first electric parking actuator 31.

[0022] The second brake ECU 80 activates the second hydraulic braking device 27. On the other hand, the second brake ECU 80 does not control the electric parking device 30. In this embodiment, the second brake ECU 80 corresponds to the "third control device." The second brake ECU 80 has a processing circuit 81. The processing circuit 81 has a CPU and a memory. The memory stores a control program for activating the second hydraulic braking device 27. The CPU executes this control program, which allows the processing circuit 81 to activate the second hydraulic braking device 27.

[0023] The redundant ECU 90 does not control the hydraulic braking device 25. On the other hand, the redundant ECU 90 operates the second electric parking actuator 32. In this respect, the redundant ECU 90 corresponds to the "second control device."

[0024] The redundant ECU 90 has a processing circuit 91 and a drive circuit 93. The processing circuit 91 has a CPU and a memory. The memory stores a control program for operating the second electric parking actuator 32. The CPU executes this control program, which enables the processing circuit 91 to operate the second electric parking actuator 32.

[0025] The drive circuit 93 is a circuit for driving the electric motor of the second electric parking actuator 32. When the drive circuit 93 operates based on a command from the processing circuit 91, the drive circuit 93 outputs a drive signal. The electric motor is driven based on the drive signal, thereby operating the second electric parking actuator 32.

[0026] The braking control system 60 includes a second in-vehicle network for communication among a plurality of control devices related to vehicle braking. The second in-vehicle network has a braking communication line 61. An example of the braking communication line 61 is a CAN bus. The first braking ECU 70, the second braking ECU 80, and the redundant ECU 90 can communicate with each other via the braking communication line 61. On the other hand, the braking communication line 61 cannot be used for communication with ECUs other than those constituting the braking control system 60.

[0027] <Processing Flow for Determining That an Abnormality Has Occurred in the First Brake ECU or That Communication Between the First Brake ECU and the Redundant ECU Using the Brake Communication Line 61 Is Not Normal> With reference to Figure 3 , the processing flow for determining an abnormality that is executed when the second brake ECU 80 and the redundant ECU 90 are normal will be described. Here, the processing flow for determining that an abnormality has occurred in the first brake ECU 70 or that communication between the first brake ECU 70 and the redundant ECU 90 using the brake communication line 61 is not normal will be described. Figure 3(a) shows a series of processing executed by the second brake ECU 80. Figure 3(b) shows a series of processing executed by the redundant ECU 90.

[0028] 3A, in step S11, the processing circuit 81 of the second brake ECU 80 transmits a monitoring signal to the first brake ECU 70 via the first global communication line 201. The monitoring signal is a signal for confirming whether the destination ECU is operating normally.

[0029] When the first brake ECU 70 receives the monitoring signal from the first global communication line 201, the processing circuit 71 of the first brake ECU 70 transmits a reply signal, which is a response signal to the monitoring signal, to the second brake ECU 80 via the first global communication line 201.

[0030] In this way, if the second brake ECU 80 can receive the reply signal transmitted from the first brake ECU 70 to the first global communication line 201, the second brake ECU 80 can determine that the first brake ECU 70 is normal. However, if an abnormality occurs in the first brake ECU 70 or if communication between the second brake ECU 80 and the first brake ECU 70 via the first global communication line 201 is not normal, the second brake ECU 80 cannot receive the reply signal from the first brake ECU 70 via the first global communication line 201.

[0031] In the following step S13, the processing circuit 81 of the second brake ECU 80 transmits a monitoring signal to the first brake ECU 70 via the brake communication line 61. If the first brake ECU 70 receives the monitoring signal from the brake communication line 61, the processing circuit 71 of the first brake ECU 70 transmits a reply signal in response to the monitoring signal to the second brake ECU 80 via the brake communication line 61.

[0032] In this way, if the second brake ECU 80 can receive the reply signal transmitted from the first brake ECU 70 to the brake communication line 61, the second brake ECU 80 can determine that the first brake ECU 70 is normal. However, if an abnormality occurs in the first brake ECU 70 or if communication between the second brake ECU 80 and the first brake ECU 70 via the brake communication line 61 is not normal, the second brake ECU 80 cannot receive the reply signal from the first brake ECU 70 via the brake communication line 61.

[0033] The processing circuit 81 of the second brake ECU 80 executes the communication determination process of step S15 when a predetermined determination time has elapsed since the monitoring signal was transmitted to the first brake ECU 70 via the brake communication line 61. In the communication determination process of step S15, the processing circuit 81 determines whether or not communication with the first brake ECU 70 was successful by executing the processes of steps S11 and S13. If both the second brake ECU 80 cannot receive a reply signal from the first global communication line 201 and the second brake ECU 80 cannot receive a reply signal from the brake communication line 61, the processing circuit 81 determines that communication between the second brake ECU 80 and the first brake ECU 70 is not normal. If the second brake ECU 80 can receive a reply signal from the first global communication line 201 but cannot receive a reply signal from the brake communication line 61, the processing circuit 81 determines that the first brake ECU 70 is normal but the communication using the brake communication line 61 may not be normal. Conversely, if the second brake ECU 80 can receive a reply signal from the brake communication line 61 but cannot receive a reply signal from the first global communication line 201, the processing circuit 81 determines that the first brake ECU 70 is normal but the communication using the first global communication line 201 may not be normal. Furthermore, if the second brake ECU 80 can receive a reply signal from both the first global communication line 201 and the brake communication line 61, the processing circuit 81 determines that the first brake ECU 70 is normal and that communication between the first brake ECU 70 and the second brake ECU 80 using the first global communication line 201 and the brake communication line 61 is normal.

[0034] Then, in step S17, the processing circuit 81 transmits communication availability information, which is information relating to the result of the communication determination process in step S15, to the redundant ECU 90 via the braking communication line 61. Thereafter, the processing circuit 81 ends the series of processes shown in FIG.

[0035] 3B, when the redundant ECU 90 receives the communication availability information transmitted by the second brake ECU 80 in step S17, the processing circuit 91 of the redundant ECU 90 executes step S21. In step S21, the processing circuit 91 transmits a monitoring signal to the first brake ECU 70 via the brake communication line 61.

[0036] When the first brake ECU 70 receives the monitoring signal from the brake communication line 61 , the processing circuit 71 of the first brake ECU 70 transmits a response signal to the monitoring signal to the redundant ECU 90 via the brake communication line 61 .

[0037] In this way, if the redundant ECU 90 can receive the reply signal transmitted from the first brake ECU 70 to the brake communication line 61, the redundant ECU 90 can determine that the first brake ECU 70 is normal. However, if an abnormality occurs in the first brake ECU 70 or if communication between the redundant ECU 90 and the first brake ECU 70 via the brake communication line 61 is not normal, the redundant ECU 90 cannot receive the reply signal from the brake communication line 61.

[0038] The processing circuit 91 of the redundant ECU 90 executes a communication determination process in step S23 when a predetermined determination time has elapsed since the time the monitoring signal was transmitted to the first brake ECU 70. In the communication determination process in step S23, the processing circuit 91 determines the following two points.

[0039] Whether or not an abnormality has occurred in the first brake ECU 70. Whether or not the communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is normal.

[0040] For example, if both of the following conditions (A1) and (A2) are satisfied, the processing circuit 91 determines that an abnormality has occurred in the first brake ECU 70. On the other hand, if at least one of the conditions (A1) and (A2) is not satisfied, the processing circuit 91 determines that the first brake ECU 70 is normal.

[0041] (A1) The communication availability information received from the second brake ECU 80 is information indicating that communication between the second brake ECU 80 and the first brake ECU 70 is not normal. (A2) The communication between the redundant ECU 90 and the first brake ECU 70 is not normal.

[0042] Furthermore, if the condition (A2) is not satisfied under the condition (A1) being satisfied, the processing circuit 91 determines that the communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is not normal. On the other hand, if the condition (A2) is satisfied under the condition (A1) being satisfied, the processing circuit 91 determines that the communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is normal.

[0043] Then, in step S25, the processing circuit 91 transmits information indicating the result of the communication determination process in step S23 to the second brake ECU 80 via the brake communication line 61. Thereafter, the processing circuit 91 ends the series of processes shown in FIG.

[0044] <Processing flow when determining that an abnormality has occurred in the redundant ECU> The processing flow when determining that an abnormality has occurred in the redundant ECU 90 when the first brake ECU 70 and the second brake ECU 80 are normal will be described with reference to Figure 4. Figure 4(a) shows a series of processing executed by the second brake ECU 80. Figure 4(b) shows a series of processing executed by the first brake ECU 70.

[0045] 4A, in step S41, the processing circuit 81 of the second brake ECU 80 transmits a monitoring signal to the redundant ECU 90 via the brake communication line 61. If the redundant ECU 90 receives the monitoring signal from the brake communication line 61, the processing circuit 91 of the redundant ECU 90 transmits a response signal to the monitoring signal to the second brake ECU 80 via the brake communication line 61.

[0046] In this way, if the second brake ECU 80 can receive the reply signal transmitted from the redundant ECU 90 to the brake communication line 61, the second brake ECU 80 can determine that the redundant ECU 90 is normal. However, if an abnormality occurs in the redundant ECU 90 or if communication between the second brake ECU 80 and the redundant ECU 90 via the brake communication line 61 is not normal, the second brake ECU 80 cannot receive the reply signal from the brake communication line 61.

[0047] The processing circuit 81 of the second brake ECU 80 executes a communication determination process in step S43 when a predetermined determination time has elapsed since the time the monitoring signal was transmitted. In the communication determination process in step S43, the processing circuit 81 determines whether communication between the second brake ECU 80 and the redundant ECU 90 is normal. If the second brake ECU 80 is able to receive a reply signal from the redundant ECU 90, the processing circuit 81 determines that communication between the second brake ECU 80 and the redundant ECU 90 is normal. On the other hand, if the second brake ECU 80 is unable to receive a reply signal from the redundant ECU 90, the processing circuit 81 determines that communication between the second brake ECU 80 and the redundant ECU 90 is not normal.

[0048] Then, in step S45, the processing circuit 81 transmits communication availability information, which is information relating to the result of the communication determination process in step S43, to the first brake ECU 70 via the brake communication line 61. Thereafter, the processing circuit 81 ends the series of processes shown in FIG.

[0049] 4B, when the first brake ECU 70 receives the communication availability information transmitted by the second brake ECU 80 in step S45, the processing circuit 71 of the first brake ECU 70 executes step S51. In step S51, the processing circuit 71 transmits a monitoring signal to the redundant ECU 90 via the brake communication line 61.

[0050] If the redundant ECU 90 receives the monitoring signal from the braking communication line 61 , the processing circuit 91 of the redundant ECU 90 transmits a response signal to the monitoring signal to the first braking ECU 70 via the braking communication line 61 .

[0051] In this way, if the first brake ECU 70 can receive the reply signal transmitted from the redundant ECU 90 to the brake communication line 61, the first brake ECU 70 can determine that the redundant ECU 90 is normal. However, if an abnormality occurs in the redundant ECU 90 or if communication between the redundant ECU 90 and the first brake ECU 70 via the brake communication line 61 is not normal, the first brake ECU 70 cannot receive the reply signal from the brake communication line 61.

[0052] The processing circuit 71 of the first brake ECU 70 executes a communication determination process in step S53 when a predetermined determination time has elapsed since the time the monitoring signal was transmitted to the redundant ECU 90. In the communication determination process in step S53, the processing circuit 71 determines whether an abnormality has occurred in the redundant ECU 90. For example, if both of the following conditions (A3) and (A4) are met, the processing circuit 71 determines that an abnormality has occurred in the redundant ECU 90. On the other hand, if at least one of the conditions (A3) and (A4) is not met, the processing circuit 71 determines that the redundant ECU 90 is normal. However, if either one of the conditions (A3) and (A4) is met, it can be assumed that communication using the brake communication line 61 is abnormal.

[0053] (A3) Communication between the second brake ECU 80 and the redundant ECU 90 via the brake communication line 61 is not normal. (A4) Communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is not normal.

[0054] In step S55, the processing circuit 71 transmits information indicating the result of the communication determination process in step S53 to the second brake ECU 80 via the brake communication line 61. This allows the first brake ECU 70 and the second brake ECU 80 to share information about whether the redundant ECU 90 is normal or abnormal. Thereafter, the processing circuit 71 ends the series of processes shown in FIG. 4B.

[0055] <Processing Flow When Determining That Communication Using the First Global Communication Line Is Not Normal> The processing flow when determining that communication using the first global communication line 201 is not normal when the multiple ECUs 70, 80, and 90 are normal will be described with reference to Figure 5. Figure 5(a) shows a series of processes executed by the integrated ECU 51. Figure 5(b) shows a series of processes executed by the redundant ECU 90. Figure 5(c) shows a series of processes executed by the first brake ECU 70 and the second brake ECU 80.

[0056] As shown in FIG. 5A, in step S111, the processing circuit of the integrated ECU 51 transmits a monitoring signal to the first brake ECU 70 and the second brake ECU 80 via the first global communication line 201.

[0057] When the first brake ECU 70 receives the monitoring signal from the first global communication line 201, the processing circuit 71 of the first brake ECU 70 transmits a reply signal to the monitoring signal to the integrated ECU 51 via the first global communication line 201. When the second brake ECU 80 receives the monitoring signal from the first global communication line 201, the processing circuit 81 of the second brake ECU 80 transmits a reply signal to the monitoring signal to the integrated ECU 51 via the first global communication line 201.

[0058] In this way, if the integrated ECU 51 can receive a reply signal from at least one of the first brake ECU 70 and the second brake ECU 80 via the first global communication line 201, it can be assumed that communication using the first global communication line 201 is normal. However, if the integrated ECU 51 cannot receive a reply signal from either the first brake ECU 70 or the second brake ECU 80, it can be assumed that communication using the first global communication line 201 may not be normal.

[0059] The processing circuit of the integrated ECU 51 executes a communication determination process in step S113 when a predetermined determination time has elapsed since the time the monitoring signal was transmitted to the first global communication line 201. In the communication determination process in step S113, the processing circuit determines whether the communication using the first global communication line 201 is normal. If the integrated ECU 51 cannot receive a reply signal from either the first brake ECU 70 or the second brake ECU 80, the processing circuit determines that the communication using the first global communication line 201 is abnormal. If the integrated ECU 51 can receive a reply signal from at least one of the first brake ECU 70 and the second brake ECU 80, the processing circuit determines that the communication using the first global communication line 201 is normal.

[0060] In step S115, the processing circuit of the integrated ECU 51 transmits information relating to the result of the communication determination process in step S113 to the redundant ECU 90 via the second global communication line 202. Thereafter, the processing circuit ends the series of processes shown in FIG.

[0061] 5B, when the redundant ECU 90 receives the information transmitted from the integrated ECU 51 in step S115, the processing circuit 91 of the redundant ECU 90 executes step S121. In step S121, the processing circuit 91 transmits a monitoring signal to the first brake ECU 70 and the second brake ECU 80 via the brake communication line 61.

[0062] If the first brake ECU 70 and the second brake ECU 80 are operating normally and communication with the ECUs 70, 80, and 90 via the brake communication line 61 is normal, each of the first brake ECU 70 and the second brake ECU 80 can receive the monitoring signal transmitted from the redundant ECU 90. As shown in FIG. 5C, in step S131, the processing circuit 71 of the first brake ECU 70 and the processing circuit 81 of the second brake ECU 80 each transmits a reply signal in response to the monitoring signal to the redundant ECU 90 via the brake communication line 61. Then, the processing circuits 71 and 81 end the series of processes shown in FIG. 5C.

[0063] When a predetermined determination time has elapsed since the monitoring signal was transmitted to the first brake ECU 70 and the second brake ECU 80, the processing circuit 91 of the redundant ECU 90 executes the communication determination process of step S123.

[0064] If the first brake ECU 70 and the second brake ECU 80 are normal and communication with the ECUs 70, 80, and 90 using the brake communication line 61 is normal, the redundant ECU 90 can receive the reply signals sent by the first brake ECU 70 and the second brake ECU 80 from the brake communication line 61 before the communication determination process of step S123 is started.

[0065] In the communication determination process of step S123, the processing circuit 91 determines whether the communication between the redundant ECU 90 and the first brake ECU 70 and the second brake ECU 80 via the brake communication line 61 is normal. In the following step S125, a message that the communication using the first global communication line 201 is not normal is transmitted to the first brake ECU 70 and the second brake ECU 80 via the brake communication line 61. Thereafter, the processing circuit 91 ends the series of processes shown in FIG. 5B.

[0066] <Processing flow for parking braking when the brake control system is normal> The processing flow when the electric parking device 30 is operated when the brake control system 60 is normal will be described with reference to Figure 6. Figure 6(a) shows a series of processes executed by the first brake ECU 70. Figure 6(b) shows a series of processes executed by the redundant ECU 90. Here, "the brake control system 60 is normal" means that all of the following conditions (B1) to (B4) are met.

[0067] (B1) All ECUs 70, 80, 90 are normal. (B2) The first brake ECU 70 can receive the parking brake operation request via the first global communication line 201.

[0068] (B3) The redundant ECU 90 can receive the parking brake operation request via the second global communication line 202. (B4) Communication between the plurality of ECUs 70, 80, 90 via the brake communication line 61 is normal.

[0069] The processing circuit 71 of the first brake ECU 70 repeatedly executes the series of processes shown in FIG. 6A. In step S211, the processing circuit 71 of the first brake ECU 70 determines whether the first brake ECU 70 has received a parking brake operation request via the first global communication line 201. If the first brake ECU 70 has received a parking brake operation request (YES in S211), the processing circuit 71 proceeds to step S213. On the other hand, if the first brake ECU 70 has not received a parking brake operation request (NO in S211), the processing circuit 71 temporarily terminates the series of processes shown in FIG. 6A.

[0070] In step S213, the processing circuit 71 activates the first electric parking actuator 31 based on the parking brake operation request received via the first global communication line 201. If the parking brake operation request is an apply request, the processing circuit 71 activates the first electric parking actuator 31 to generate a parking braking force on the first wheel 11. If the parking brake operation request is a release request, the processing circuit 71 activates the first electric parking actuator 31 to release the state in which the parking braking force is being generated on the first wheel 11.

[0071] In the following step S215, the processing circuit 71 transmits an operation instruction to the redundant ECU 90 via the brake communication line 61. The operation instruction is an instruction corresponding to the parking brake operation request received by the first brake ECU 70 via the first global communication line 201. Thereafter, the processing circuit 71 temporarily ends the series of processes shown in FIG.

[0072] The processing circuit 91 of the redundant ECU 90 repeatedly executes the series of processes shown in FIG. 6B. In step S221, the processing circuit 91 determines whether the redundant ECU 90 has received the activation command transmitted by the first brake ECU 70 to the brake communication line 61. If the redundant ECU 90 has not received the activation command (S221: NO), the processing circuit 91 temporarily terminates the series of processes shown in FIG. 6B. On the other hand, if the redundant ECU 90 has received the activation command (S221: YES), the processing circuit 91 proceeds to step S223.

[0073] In step S223, the processing circuit 91 activates the second electric parking actuator 32 based on the activation command received from the first brake ECU 70. If the activation command is a command corresponding to an apply request, the processing circuit 91 activates the second electric parking actuator 32 to generate parking braking force at the second wheel 12. If the activation command is a command corresponding to a release request, the processing circuit 91 activates the second electric parking actuator 32 to release the state in which parking braking force is being generated at the second wheel 12. Thereafter, the processing circuit 91 temporarily ends the series of processes shown in FIG. 6B.

[0074] <Processing flow related to parking braking when it is determined that an abnormality has occurred in the first brake ECU> The processing flow when an abnormality has occurred in the first brake ECU 70 while the redundant ECU 90 is operating normally will be described with reference to Figure 7. Figure 7 shows a series of processes executed by the redundant ECU 90. The processing circuit 91 of the redundant ECU 90 repeatedly executes this series of processes.

[0075] In step S311, the processing circuit 91 determines whether the redundant ECU 90 has received a parking brake activation request via the second global communication line 202. If the redundant ECU 90 has received a parking brake activation request (YES in step S311), the processing circuit 91 proceeds to step S313. On the other hand, if the redundant ECU 90 has not received a parking brake activation request (NO in step S311), the processing circuit 91 temporarily terminates the series of processes shown in FIG. 7 .

[0076] In step S313, the processing circuit 91 activates the second electric parking actuator 32 based on the parking brake operation request received via the second global communication line 202. If the parking brake operation request is an apply request, the processing circuit 91 activates the second electric parking actuator 32 to generate a parking braking force on the second wheel 12. If the parking brake operation request is a release request, the processing circuit 91 activates the second electric parking actuator 32 to release the state in which the parking braking force is being generated on the second wheel 12. Thereafter, the processing circuit 91 temporarily ends the series of processes shown in FIG.

[0077] <Processing flow related to parking braking when it is determined that an abnormality has occurred in the redundant ECU> The processing flow when an abnormality has occurred in the redundant ECU 90 while the first brake ECU 70 is operating normally will be described with reference to Figure 8. Figure 8 shows a series of processing steps executed by the first brake ECU 70. The processing circuit 71 of the first brake ECU 70 repeatedly executes this series of processing steps.

[0078] In step S411, the processing circuit 71 determines whether the first brake ECU 70 has received a parking brake operation request via the first global communication line 201. If the first brake ECU 70 has received a parking brake operation request (YES in step S411), the processing circuit 71 proceeds to step S413. On the other hand, if the first brake ECU 70 has not received a parking brake operation request (NO in step S411), the processing circuit 71 temporarily terminates the series of processes shown in FIG.

[0079] In step S413, the processing circuit 71 activates the first electric parking actuator 31 based on the parking brake operation request received via the first global communication line 201. If the parking brake operation request is an apply request, the processing circuit 71 activates the first electric parking actuator 31 to generate a parking braking force on the first wheel 11. If the parking brake operation request is a release request, the processing circuit 71 activates the first electric parking actuator 31 to release the state in which the parking braking force is being generated on the first wheel 11. Thereafter, the processing circuit 71 temporarily ends the series of processes shown in FIG.

[0080] <Processing flow related to parking braking when communication between the first brake ECU and the redundant ECU via the brake communication line is abnormal> With reference to Figure 9, a processing flow related to parking braking when communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is abnormal when the multiple ECUs 70, 80, and 90 are normal. Figure 9(a) shows a series of processing executed by the first brake ECU 70. Figure 9(b) shows a series of processing executed by the redundant ECU 90. The processing circuit 71 of the first brake ECU 70 repeatedly executes the series of processing shown in Figure 9(a). The processing circuit 91 of the redundant ECU 90 repeatedly executes the series of processing shown in Figure 9(b).

[0081] 9A, in step S511, the processing circuit 71 of the first brake ECU 70 determines whether the first brake ECU 70 has received a parking brake operation request via the first global communication line 201. If the first brake ECU 70 has received a parking brake operation request (YES in S511), the processing circuit 71 proceeds to step S513. On the other hand, if the first brake ECU 70 has not received a parking brake operation request (NO in S511), the processing circuit 71 temporarily terminates the series of processes shown in FIG.

[0082] In step S513, the processing circuit 71 activates the first electric parking actuator 31 based on the parking brake operation request, similar to step S213 in Fig. 6A. Thereafter, the processing circuit 71 temporarily ends the series of processes shown in Fig. 9A.

[0083] 9B, in step S521, the processing circuit 91 of the redundant ECU 90 determines whether the redundant ECU 90 has received a parking brake activation request via the second global communication line 202. If the redundant ECU 90 has received a parking brake activation request (YES in S521), the processing circuit 91 proceeds to step S523. On the other hand, if the redundant ECU 90 has not received a parking brake activation request (NO in S521), the processing circuit 91 temporarily terminates the series of processes shown in FIG.

[0084] In step S523, the processing circuit 91 determines whether the parking brake operation request received by the redundant ECU 90 is a release request. If the parking brake operation request is a release request (S523: YES), the processing circuit 91 proceeds to step S525. On the other hand, if the parking brake operation request is not a release request (S523: NO), the parking brake operation request is an apply request, and the processing circuit 91 temporarily terminates the series of processes shown in FIG. 9B. In other words, if the parking brake operation request is an apply request, the processing circuit 91 does not operate the second electric parking actuator 32.

[0085] In step S525, the processing circuit 91 operates the second electric parking actuator 32 based on the release request to release the parking braking force from the second wheel 12. After that, the processing circuit 91 temporarily ends the series of processes shown in FIG.

[0086] <Processing Flow Related to Parking Braking When Communication Via First Global Communication Line is Not Normal> With reference to Figure 10 , a processing flow related to parking braking when communication via the first global communication line 201 is not normal under conditions in which communication via the second global communication line 202 and the braking communication line 61 is normal will be described. Figure 10(a) shows a series of processing executed by the first brake ECU 70. Figure 10(b) shows a series of processing executed by the redundant ECU 90. The processing circuit 71 of the first brake ECU 70 repeatedly executes the series of processing shown in Figure 10(a). The processing circuit 91 of the redundant ECU 90 repeatedly executes the series of processing shown in Figure 10(b).

[0087] 10B, in step S621, the processing circuit 91 of the redundant ECU 90 determines whether the redundant ECU 90 has received a parking brake operation request via the second global communication line 202. If the redundant ECU 90 has received a parking brake operation request (S621: YES), the processing circuit 91 proceeds to step S623. On the other hand, if the redundant ECU 90 has not received a parking brake operation request (S621: NO), the processing circuit 91 temporarily terminates the series of processes shown in FIG. 10B. In step S623, the processing circuit 91 transmits the received parking brake operation request to the first brake ECU 70 via the brake communication line 61.

[0088] 10A, in step S611, the processing circuit 71 of the first brake ECU 70 determines whether the first brake ECU 70 has received a parking brake operation request via the brake communication line 61. If the first brake ECU 70 has received a parking brake operation request (YES in S611), the processing circuit 71 proceeds to step S613. On the other hand, if the first brake ECU 70 has not received a parking brake operation request (NO in S611), the processing circuit 71 temporarily terminates the series of processes shown in FIG.

[0089] In step S613, the processing circuit 71 activates the first electric parking actuator 31 based on the parking brake activation request, similar to step S213 in Fig. 6A. In the following step S615, the processing circuit 71 transmits an activation command corresponding to the received parking brake activation request to the redundant ECU 90 via the brake communication line 61. Thereafter, the processing circuit 71 temporarily ends the series of processes shown in Fig. 10A.

[0090] 10B, after executing step S623, the processing circuit 91 of the redundant ECU 90 proceeds to step S625. In step S625, the processing circuit 91 determines whether the redundant ECU 90 has received an activation command via the braking communication line 61. If the redundant ECU 90 has not received an activation command (S625: NO), the processing circuit 91 repeatedly executes the determination in step S625 until the redundant ECU 90 receives an activation command. If the redundant ECU 90 has received an activation command (S625: YES), the processing circuit 91 proceeds to step S627.

[0091] In step S627, the processing circuit 91 activates the second electric parking actuator 32 based on the activation command, similar to step S223 in Fig. 6B. Thereafter, the processing circuit 91 temporarily ends the series of processes shown in Fig. 10B.

[0092] <Functions and Effects of the Present Embodiment> (1) The brake control system 60 includes a first brake ECU 70 that operates the first electric parking actuator 31 and a redundant ECU 90 that operates the second electric parking actuator 32. The first brake ECU 70 can receive a parking brake operation request via the first global communication line 201. The redundant ECU 90 can receive a parking brake operation request via the second global communication line 202. When the first brake ECU 70 receives a parking brake operation request via the first global communication line 201, it operates the first electric parking actuator 31 based on the parking brake operation request. Furthermore, the first brake ECU 70 transmits an operation command corresponding to the parking brake operation request to the redundant ECU 90 via the brake communication line 61, as indicated by arrow X2 in FIG. 2 .

[0093] When the first brake ECU 70 is normal, the redundant ECU 90 operates the second electric parking actuator 32 based on an operation command received via the brake communication line 61. On the other hand, when an abnormality occurs in the first brake ECU 70, the redundant ECU 90 operates the second electric parking actuator 32 based on a parking brake operation request received via the second global communication line 202.

[0094] That is, in the brake control system 60, the redundant ECU 90 can operate the second electric parking actuator 32 regardless of whether the first brake ECU 70 is normal or not. This allows the brake control system 60 to make the electric parking device 30 redundant.

[0095] (2) The brake control system 60 further includes a second brake ECU 80. The second brake ECU 80 determines whether communication with the first brake ECU 70 via the first global communication line 201 is normal. The second brake ECU 80 also determines whether communication with the first brake ECU 70 via the brake communication line 61 is normal. Meanwhile, the redundant ECU 90 determines whether communication with the first brake ECU 70 via the brake communication line 61 is normal. If communication between the second brake ECU 80 and the first brake ECU 70 is not normal and communication between the redundant ECU 90 and the first brake ECU 70 is not normal, there is a possibility that an abnormality has occurred in the first brake ECU 70.

[0096] Therefore, the second brake ECU 80 transmits communication availability information, which is information regarding whether communication between the second brake ECU 80 and the first brake ECU 70 is normal, to the redundant ECU 90 via the brake communication line 61. If both of the following are true: the communication availability information received from the second brake ECU 80 indicates that communication between the second brake ECU 80 and the first brake ECU 70 is not normal, and the communication between the redundant ECU 90 and the first brake ECU 70 is not normal, the redundant ECU 90 determines that an abnormality has occurred in the first brake ECU 70. In other words, the redundant ECU 90 can determine whether an abnormality has occurred in the first brake ECU 70 without making the brake communication line 61 redundant in the brake control system 60.

[0097] (3) Even if the first brake ECU 70 is operating normally, communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 may become abnormal. In this case, it becomes difficult for the first brake ECU 70 and the redundant ECU 90 to cooperate. If the first brake ECU 70 and the redundant ECU 90 cannot cooperate, there is a possibility that, even though one of the multiple electric parking actuators 31, 32 can release the parking braking force from being applied to the wheels, the other electric parking actuator may maintain the parking braking force from being applied to the wheels. In this case, there is a possibility that a dragging sensation may continue to occur when the vehicle 10 is subsequently driven.

[0098] In this regard, in the brake control system 60, in the above case, when the redundant ECU 90 receives a release request as a parking brake operation request via the second global communication line 202, the processing circuit 91 operates the second electric parking actuator 32 to release the state in which the parking braking force is being applied to the second wheel 12. This prevents the state in which the parking braking force is being applied to the second wheel 12 from being maintained even though the state in which the parking braking force is being applied to the first wheel 11 can be released. Therefore, the vehicle 10 can then travel without a dragging sensation.

[0099] In the above case, if the first brake ECU 70 can receive the parking brake operation request via the first global communication line 201, the processing circuit 71 operates the first electric parking actuator 31 based on the parking brake operation request. Therefore, the brake control system 60 can generate a parking braking force on the vehicle 10 even if communication using the brake communication line 61 is not normal.

[0100] (4) Communication using the first global communication line 201 may become abnormal. In the brake control system 60, the redundant ECU 90 can receive a parking brake operation request via the second global communication line 202. Therefore, when communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is normal, the processing circuit 91 of the redundant ECU 90 transmits the parking brake operation request received via the second global communication line 202 to the first brake ECU 70 via the brake communication line 61. When the first brake ECU 70 receives the parking brake operation request via the brake communication line 61, the processing circuit 71 activates the first electric parking actuator 31 based on the parking brake operation request. The processing circuit 71 also transmits an operation command corresponding to the parking brake operation request to the redundant ECU 90 via the brake communication line 61. When the redundant ECU 90 receives the operation instruction, the processing circuit 91 operates the second electric parking actuator 32 based on the operation instruction.

[0101] Therefore, even if communication using the first global communication line 201 is not normal, the brake control system 60 can operate the electric parking device 30 as long as the redundant ECU 90 can receive a parking brake operation request via the second global communication line 202.

[0102] (5) The brake control system 60 includes a redundant ECU 90 in addition to the first brake ECU 70 and the second brake ECU 80 that operate the hydraulic brake device 25. The first brake ECU 70 and the redundant ECU 90 can operate the electric parking device 30. Therefore, the brake control system 60 can make the electric parking device 30 redundant without making design changes to the configuration of the second brake ECU 80 that operates the second hydraulic brake device 27.

[0103] <Modifications> The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0104] When the redundant ECU 90 receives a parking brake operation request via the second global communication line 202 under conditions in which communication using the first global communication line 201 is not normal, the processing circuit 91 of the redundant ECU 90 does not have to transmit the parking brake operation request to the first brake ECU 70 via the brake communication line 61. Even in this case, the processing circuit 91 activates the second electric parking actuator 32 based on the parking brake operation request received via the second global communication line 202. Therefore, the brake control system 60 can generate a parking braking force on the vehicle 10 even if communication using the first global communication line 201 is not normal.

[0105] When the first brake ECU 70 is functioning normally but communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is not functioning normally, the processing circuit 91 may receive an apply request as a parking brake operation request via the second global communication line 202. In this case, the processing circuit 91 may operate the second electric parking actuator 32 based on the apply request. For example, even if communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is not functioning normally, if communication between the second brake ECU 80 and the redundant ECU 90 via the brake communication line 61 is normal, the first brake ECU 70 can communicate with the redundant ECU 90 via the second brake ECU 80. Therefore, in this case, when the first brake ECU 70 and the redundant ECU 90 receive an apply request, they may each operate the electric parking actuators 31, 32 to generate parking braking force at the wheels 11, 12.

[0106] Even if communication between the first brake ECU 70 and the redundant ECU 90 via the brake communication line 61 is normal, communication between the second brake ECU 80 and the redundant ECU 90 via the brake communication line 61 may not be normal. In this case, the redundant ECU 90 may prohibit the second wheel 12 from generating a parking braking force. However, when a release request is received, the redundant ECU 90 preferably operates the second electric parking actuator 32 based on the release request.

[0107] If the communication between the second brake ECU 80 and the first brake ECU 70 via the first global communication line 201 is not normal, the first brake ECU 70 may not be able to receive the parking brake operation request via the first global communication line 201. Therefore, if the communication with the first brake ECU 70 via the first global communication line 201 is not normal, the second brake ECU 80 may transmit communication availability information indicating that the communication between the second brake ECU 80 and the first brake ECU 70 is not normal to the redundant ECU 90 via the brake communication line 61, regardless of whether the communication with the first brake ECU 70 via the brake communication line 61 is normal.

[0108] -If only one of the multiple electric parking actuators 31, 32 can generate a parking braking force, the parking braking force generated by activating that one actuator may be greater than the parking braking force generated when both of the multiple electric parking actuators 31, 32 are activated.

[0109] Although the first brake ECU 70 and the redundant ECU 90 are normal, an abnormality may occur in the second brake ECU 80. Even in this case, the first brake ECU 70 can receive a parking brake operation request via the first global communication line 201. Furthermore, the first brake ECU 70 can transmit an operation command corresponding to the parking brake operation request to the redundant ECU 90 via the brake communication line 61. Therefore, the brake control system 60 may proceed with the process shown in FIG. 6 . As a result, the brake control system 60 can operate the electric parking device 30 even if an abnormality occurs in the second brake ECU 80.

[0110] The braking control system 60 includes a redundant ECU 90 in addition to the multiple braking ECUs 70, 80, and the first braking ECU 70 functions as the first control device and the redundant ECU 90 functions as the second control device. However, this is not limited to this. For example, the second braking ECU 80 may function as the second control device. In this case, the braking control system does not need to include the redundant ECU 90.

[0111] When an abnormality occurs in the integrated ECU 51, the integrated ECU 51 does not transmit a parking brake operation request to either the first global communication line 201 or the second global communication line 202. Even in this case, the redundant ECU 90 can receive information transmitted by the shift ECU 52 to the second global communication line 202. Therefore, the redundant ECU 90 analyzes the information received from the shift ECU 52, and when it determines that a parking brake force should be generated, transmits a parking brake operation request to the first brake ECU 70 via the brake communication line 61. In this case, the processing circuit 71 of the first brake ECU 70 activates the first electric parking actuator 31 based on the received parking brake operation request. The processing circuit 71 may also transmit an operation command corresponding to the parking brake operation request to the redundant ECU 90 via the brake communication line 61. The processing circuit 91 of the redundant ECU 90 activates the second electric parking actuator 32 based on the received operation command. This allows the brake control system 60 to operate the electric parking device 30 even if an abnormality occurs in the integrated ECU 51.

[0112] The processing circuits 71, 81, and 91 are not limited to those including a CPU and ROM and executing software processing. That is, the processing circuits 71, 81, and 91 may have any of the following configurations (a), (b), and (c):

[0113] (a) The processing circuits 71, 81, and 91 each include one or more processors that execute various processes according to a computer program. The processor includes a CPU and memory such as RAM and ROM. The memory stores program code or instructions configured to cause the CPU to execute processes. Memory, i.e., computer-readable media, includes any available media that can be accessed by a general-purpose or special-purpose computer.

[0114] (b) The processing circuits 71, 81, and 91 each include one or more dedicated hardware circuits that perform various processes. Examples of dedicated hardware circuits include application-specific integrated circuits (ASICs) and FPGAs. ASIC stands for "Application Specific Integrated Circuit." FPGA stands for "Field Programmable Gate Array."

[0115] (c) The processing circuits 71, 81, and 91 each include one or more processors that execute some of the various processes in accordance with a computer program, and one or more dedicated hardware circuits that execute the remaining processes of the various processes.

[0116] <Other Technical Ideas> The technical ideas that can be understood from the above-described embodiment and modified examples will be described below. [Supplementary Note 1] It is preferable that the first control device, the second control device, and the third control device are control devices related to vehicle braking.

[0117] [Supplementary Note 2] It is preferable that the vehicle includes a command control device that is a control device outside the braking control system, and that the command control device transmits the parking brake operation request to the first in-vehicle network.

[0118] [Appendix 3] When the second control device receives the parking brake operation request via the first in-vehicle network indicating that parking braking force is to be generated in a situation where the first control device is normal but communication between the first control device and the second control device via the second in-vehicle network is not normal, it is preferable that the second control device maintains a state in which parking braking force is not being generated on the second wheel.

[0119] It should be noted that the expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

Claims

1. A braking control system applied to a vehicle having a first wheel and a second wheel, a first electric parking actuator configured to generate a parking braking force on the first wheel, and a second electric parking actuator configured to generate a parking braking force on the second wheel, comprising: a first control device that operates the first electric parking actuator; and a second control device that operates the second electric parking actuator, wherein each of the first control device and the second control device is capable of receiving a parking brake operation request, which is a request for parking braking, via a first in-vehicle network, and the second control device is capable of communicating with the first control device via a second in-vehicle network, wherein, when the parking brake operation request is received via the first in-vehicle network, the first control device operates the first electric parking actuator based on the parking brake operation request and transmits an operation command corresponding to the parking brake operation request to the second control device via the second in-vehicle network, and when the first control device is normal, the second control device operates the second electric parking actuator based on the operation command received via the second in-vehicle network, A braking control system that operates the second electric parking actuator based on the parking brake operation request received via the first in-vehicle network when an abnormality occurs in the first control device.

2. A braking control system as described in claim 1, comprising a third control device configured to be able to communicate with the first control device via the first in-vehicle network and to be able to communicate with the second control device via the second in-vehicle network, wherein the third control device is configured to transmit communication availability information, which is information regarding whether communication with the first control device is normal, to the second control device via the second in-vehicle network, and the second control device determines that an abnormality has occurred in the first control device when both the communication availability information received from the third control device is information indicating that communication between the third control device and the first control device is not normal and the communication between the second control device and the first control device is not normal.

3. A braking control system as described in claim 1 or claim 2, wherein when the second control device receives the parking brake operation request via the first in-vehicle network indicating that the generation of the parking braking force should be released under a situation where the first control device is normal but communication between the first control device and the second control device via the second in-vehicle network is not normal, the second control device operates the second electric parking actuator to release the state in which the parking braking force is being generated on the second wheel.

4. The brake control system described in claim 2, wherein the first in-vehicle network includes a first global communication line for transmitting information to the first control device and the third control device, and a second global communication line for transmitting information to the second control device, and the second control device, when receiving the parking brake operation request via the second global communication line under a situation where the first control device is normal and communication between the second control device and the first control device via the second in-vehicle network is normal, but communication using the first global communication line is abnormal, transmits the parking brake operation request to the first control device via the second in-vehicle network, and the first control device operates the first electric parking actuator based on the parking brake operation request received via the second in-vehicle network, and transmits an operation instruction corresponding to the parking brake operation request to the second control device via the second in-vehicle network.

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